Parting tool chatter

[Steamchick]

My rear tool post is centred about 1 1/2 " from the workpiece. The engagement of the cross-slide to saddle is still the same and the same location relative to lathe axis. I can't see it matter in that the handle and part of the cross slide extend beyond the engaged part of the slides?
Tool position over the saddle over the bed should only be applying torque against the regular slide faces anyway. (Hard to discuss this without pictures).
K2

 

[bikr7549]

Apprentice707, that pic was contrived as i am not doing any parting at the moment. I do lock the carriage and tighten up the gibs when doing this operation.

 

[bikr7549]

Here are some more pictures of the setup, in particular the alignment of the tool to the cross slide dovetail. If I had tried rotating the compound axis to be perpendicular to the lathe spindle I may not have had the chatter problems as the overhang that way is much, much less. But it is even better with the new tool, almost on the cross slide dovetail centerline. Next time I need to do some parting and have the time I may go back to the old holder just to see. BTW, the new cutoff tool is about 3/32" wide, same as the old one. The new tool has a radius on the top of the tool running along its length.

 

[tim9lives]

It does look like there is a "big brother" international conspiracy. I think it is a strategic warfare by the Chinese - where the man-made virus was initially released - to de-stabilise the Western economies, so we become more dependant on imports from China, which can then inflate prices for their goods! Maybe it isn't? Just an unhappy coincidence? But nothing would surprise me...

All types of scenarios and possibilities. Could be just a screw up which was unforeseen. Very possible that it happened just as reported, a wet market.
That said, if any government were to intentionally want to harm Capitalism of the major Western Economies... a pandemic appears to be a pretty damned good weapon. But, next we would have to look at motivations. Personally I don’t think China would have been as motivated to do something like use a Bio-weapon as Putin’s Russia or the other two Rogue Nations like Iran or North Korea. Let’s not forget that we have UN sanctions on those three nations. Much less harm to their economies than to even China. Free Western Nations have taken a huge economic hit.
Furthermore, Russia has been working on Bio-weapons for decades. Russia even put bio weapons at the forefront of their triad of offensive weapons with nuclear now the last most likely weapon to use offensively.

 

[SmithDoor]

You do know it all same for CNC and Screw machines. The only difference is one use a computer and the uses reliable cams. Turrets use a machinist.

The screw machines are fully automatic the CNC is only easy to setup but most slower since they only use one tool at time.

Dave

Baronj wrote,

"That looks reminiscent of the sort of method used on auto or CNC tool changers.

However it doesn't get you away from the play in the cross slide. "

I agree with you Baronj but the main point of the vertical parting tool is it avoids the horizontal cantilever distance from the parting tool mounting point to the cutting tip. This horizontal distance is present in both front or rear parting tool set ups and this exaggerates any defficiences at the mounting point base or as you say cross or topslide. The vertical parting tool has solid metal support from the tip to the top of the cross slide.

Alan

 

[SmithDoor]

Error

 

[nautilus29]

Depending on your lathe side I would consider a thinner cutoff as well. We also use right or left cutoffs at work where the face of the cuttoff is angled. Another benefit from doing that is you can basically get rid of the dimple on your part.

 

[SmithDoor]

I agree something has been talked out.

I use thin blade even if say thicker blade
Even on 2" bar stock I use ether 0.040 or 0.060 size blade

Dave

Depending on your lathe side I would consider a thinner cutoff as well. We also use right or left cutoffs at work where the face of the cuttoff is angled. Another benefit from doing that is you can basically get rid of the dimple on your part.

 

[Richard Hed]

All types of scenarios and possibilities. Could be just a screw up which was unforeseen. Very possible that it happened just as reported, a wet market.
That said, if any government were to intentionally want to harm Capitalism of the major Western Economies... a pandemic appears to be a pretty damned good weapon. But, next we would have to look at motivations. Personally I don’t think China would have been as motivated to do something like use a Bio-weapon as Putin’s Russia or the other two Rogue Nations like Iran or North Korea. Let’s not forget that we have UN sanctions on those three nations. Much less harm to their economies than to even China. Free Western Nations have taken a huge economic hit.
Furthermore, Russia has been working on Bio-weapons for decades. Russia even put bio weapons at the forefront of their triad of offensive weapons with nuclear now the last most likely weapon to use offensively.

What abut the other rogue nation? The biggest of them all?

 

[MRA]

What's more explosive here - talking about WMD, or admitting that at home on a small bendy machine I often use the tailstock when I'm parting off and only withdraw (ahem) at the last moment

It also works better if things are a bit bendy if you go really, really, really slowly (thinking speed rather than feed, though that spoils the gag a bit!)..

 

[Steamchick]

Bikr. You were right about the quick change head being a problem. Tools outside the width of the slides cause a twist that causes chatter... the new tool holder inside the width of the slide is correct.
Well done!
K2

 

[goldstar31]

[

Bikr. You were right about the quick change head being a problem. Tools outside the width of the slides cause a twist that causes chatter... the new tool holder inside the width of the slide is correct.
Well done!
K2

Ken
In your case, I believe that you have a 8 X16 lathe similar to my SiegC4. So you can utlise the GHT rear parting tool which was designed for the Myford 7 series by the simple addition of a mild steel subplate. The simple expedient will also allow more redly available 'Myford' stuff suchas vices, vertical slides. Mine will also take such things as my GHT small dividing head and several sizes of rotary tables.

Thought that a mention might regresh memory


Best wishes

Norman

 

[Steamchick]

Sorry Norman. I don't know anything about MYFORD ML7 stuff. I only ever owned an ML3. They stopped making that in the 1960s anyway, and no spares or extras.
I made my own rear mount for a tool holder my father had made for his 1960s lathe (his Dad's). I had to drill and tap the cross-slide for the rr mount, as it is without tee-slots.
K2

 

[Steamchick]

Hi again Norman... your mention of sub-plates has prompted an idea that I could add a piece of gauge plate onto the back of the cross-slide - 4-bolt easy to dismount for working on it - so I can drill-tap for various other kit, such as fixtures for holding cylinders for boring, vertical slide, angle plates, etc.
Thanks for the prompt!
K2

 

[goldstar31]

Sorry Norman. I don't know anything about MYFORD ML7 stuff. I only ever owned an ML3. They stopped making that in the 1960s anyway, and no spares or extras.
I made my own rear mount for a tool holder my father had made for his 1960s lathe (his Dad's). I had to drill and tap the cross-slide for the rr mount, as it is without tee-slots.
K2

In a a roundabout way, I also used a plain unslotted plate As for 'Archaic stuff', I have a Perfecto vertical slide and vice- which fits both lathes and - if it warms up a bit- I am fittomg a 1950' Potts stle vertical slide.

Norman

 

[goldstar31]

In a a roundabout way, I also used a plain unslotted plate As for 'Archaic stuff', I have a Perfecto vertical slide and vice- which fits both lathes and - if it warms up a bit- I am fittomg a 1950' Potts stle vertical slide.

Norman

Apologies, I was doing my 'Hendon Days' one finger typing--- and YOU BEAT ME

 

[Steamchick]

I cheated. Used 2 fingers...
K2